I need to choose random function in C project-CodePudding

I am making C game-project and in the game I need to choose random bonuses(functions).

(below is the example of the code)

void triple_balls(){
    ...
}

void longer_paddle(){
    ...
}

void shorter_paddle(){
    ...
}

void bonus_activator(){
    //Here I must choose one of the 3 functions above
    //FIXME
}

CodePudding user response：

Use a function pointer array instead

using BonusFunc = void (*)();
BonusFunc[3] = { triple_balls, longer_paddle, shorter_paddle };

void bonus_activator(){
    BonusFunc[rand() % 3](); // just an example, don't use rand() in real code
}

CodePudding user response：

You can use std::function, to store you functions in a container. Then create an array of std::function of size 3.

#include <functional>
#include <iostream>

void triple_balls() { /* YOUR CODE */ }

void longer_paddle() { /* YOUR CODE */ }

void shorter_paddle() { /* YOUR CODE */ }

void bonus_activator(){
    std::function<void(void)> farr[3] = 
    {
        triple_balls,
        longer_paddle,
        shorter_paddle
    };
    farr[rand() % 3]();
}

CodePudding user response：

std::array{
  &triple_balls,
  &longer_paddle,
  &shorter_paddle,
}
.at(rand() % 3)();

fits in only one-line and no variables needed and the optimizer will likely reduce this into a switch-statement-like operation:

std::array{ &triple_balls, &longer_paddle, &shorter_paddle }.at(rand() % 3)();